What are the types of Food Allergy and how to prevent them ?
Allergy is an exaggerated reaction of the immune system to certain, normally harmless environmental substances. These substances are called allergens.
Types of Food Allergy
There are two types of Food Allergy: Primary and Secondary Food Allergies.
Primary Food Allergies usually first appear during childhood. The symptoms appear shortly after consumption (2 hours at most) of certain food substances.
In Secondary Food Allergy there is an underlying allergy to pollen or dust mites. Some elements in foods are similar to these allergens and may trigger allergic reactions.
Clinical symptoms in Food Allergies
- EYES: redness, watery, swelling
- MOUTH: Swelling of the lips, tongue, gums and/or larynx, itching of the mouth and throat
- SKIN: Rash, hives, redness, itching
- STOMACH: Nausea, vomiting, abdominal pain, diarrhea, heartburn
- RESPIRATORY: Nose itch, running
- LUNGS: cough, tightness in the chest, wheezing breath sounds, difficulty breathing
- ANAPHYLAXIS: Shock, drop in blood pressure, elevated pulse, brief unconsciousness
How a child describes allergy reaction
- Put hands to mouth, pull or scratch tongue, voices may change
- May comment that “Food is too spicy”
- “My tongue is hot, something is poking it”
- “My mouth is tingly, itches, or feels funny”
- “My tongue feels full, my throat feels thick”
The foods that most frequently trigger allergic reactions
Peanuts, fish, cow’s milk, wheat and chicken eggs. Allergies to cow’s milk or chicken eggs may diminish over time as children grow up. In some cases, they may in fact be able to consume the foods after a few years. However, allergies to peanuts, fish are usually life-long.
Exercise induced anaphylaxis
Usually occurs within two hours of eating the allergenic food. Onset is during physical activity.
Foods most frequently reported to have induced exercise-induced anaphylaxis:
- Wheat (omega-5-gliadin) and other grains
- Shellfish (shrimp; oysters)
- Peaches and other fruits
- Nuts especially hazelnut
- Peanuts and soy beans
The known food allergen may be hidden as an unknown ingredient or contaminant:
- Eggs – baked goods, noodles
- Milk – pies, cheese
- Soy – baked goods, candy, tv dinners
- Wheat – flours, soup mixes, snacks
- Peanut – candy, baked goods, ice cream
- Fish – seafood flavors
Identifying Food Allergy
- Allergy Specialist
- Medical history, physical exam
- Skin test
- Lab tests
- Oral food challenge
- Elimination diet
- Double-blind food challenge
Avoiding the allergens is the safest measure when suffering from food allergy. Allergy sufferers often report that the symptoms are much lesser outside of the pollen season. Many foods especially some fruits and vegetables when heated, can be consumed without a problem.
Patients who have had severe allergic reactions to food allergens in the past (Anaphylaxis: Breathing problems, dizziness, drop in blood pressure) should keep an emergency kit with them, which usually contain an antihistamine, a corticosteroid (cortisone) and an adrenaline injection.
How can one avoid development of Food Allergy?
- Identify those at risk
- Consult a doctor
- Consider breast feeding
- Maternal diet avoiding eggs, cow milk, peanuts, fish
Children and Food Allergy
- For babies, discuss formula options with doctor
- Don’t introduce solid foods too early – wait about 6 months
- Wait on foods with common allergens
- Cow milk – age 1
- Eggs – age 2
- Peanuts, nuts or fish – age 3
Differentiate food intolerance and allergy:
Food intolerance is more common than allergies and is often misconceived as food allergy. It is a physiological response to the chemicals in food. There is no immune response, no life threatening effects. Usually one develops Bloating, gas, abdominal discomfort.
Following are the intolerance events:
- Food poisoning
- Histamine toxicity (happens on consumption of cheese, wine, fish)
- Lactose intolerance
- Food additives (MSG in taste makers)
- Gluten intolerance
- Corn products
In case of true allergy – avoid food (this prevents the reactions in the immune system)
Intolerance – small amount is ok (usually tolerated by the digestive system)
Being safe from Food Allergies:
On the processed food package, read the ingredient lists on food products carefully. This will help you to trace the allergens in the food (e.g. nuts).
For people with food allergies, it can often be difficult to identify the trigger. Hence maintain an allergy book, which will help you to remember or someone else to identify substances causingallergy in you.
If you have an allergic reaction to fruit, heat it before eating. Some allergens can be destroyed this way, which can make the fruit more tolerable for you.
- Food Allergy and Anaphylaxis Network (FAAN)
- American Academy of Allergy, Asthma, and Immunology
- Food and Drug Administration
- USDA – National Agriculture Library
If you have any allergy related issues feel free to contact Allergy Specialist in Bangalore - Dr. Puneeth KN for a consultation.
About the Author
Dr Puneet. K. Nagendra
MBBS, DTCD, DNB (Pulmonary Medicine)
Presently I render my clinical services as an Allergist & Pulmonologist in Bengaluru Allergy Centr, PD Hinduja Sindhi Hospital, Excelcare Hospital and Mahapranajeeva - Speciality Centre for Respiratory diseases at Bengaluru.
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